Abstract: The course Laser Principle and Technology for undergraduates is a multi-physics subject that covers laser’s basic principle, laser modulation techniques, Q-switching techniques, etc. A virtual simulation platform “Laser V-Lab” was developed to improve students’ understanding of the complex theories and integrate theories with engineering practice. The platform consists of three main modules (laser generation, laser propagation and laser controlling), which can perform the simulation of laser output characteristics, laser transverse mode, laser modulation, Q-switching, frequency conversion, etc. Each function module has its input parameters which can be modified by the user and the calculation results can be displayed and saved. Three application examples are given: the forming process of laser transverse mode and the characteristics of high order transverse mode, influences of the output mirror’s reflectivity on the relaxation oscillation process, and the laser propagation calculation using ABCD matrix. Teaching practice shows that the virtual simulation software has increased students’ interest in learning, cultivated their engineering practical ability and promoted their creative thinking.